/**

* Copyright (c) Rich Hickey. All rights reserved.

* The use and distribution terms for this software are covered by the

* Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

* which can be found in the file epl-v10.html at the root of this distribution.

* By using this software in any fashion, you are agreeing to be bound by

* the terms of this license.

* You must not remove this notice, or any other, from this software.

**/

/* rich Jan 1, 2009 */

package clojure.lang;

import java.util.Map;

public abstract class ARef extends AReference implements IRef{

protected volatile IFn validator = null;

private volatile IPersistentMap watches = PersistentHashMap.EMPTY;

public ARef(){

super();

}

public ARef(IPersistentMap meta){

super(meta);

}

void validate(IFn vf, Object val){

try

{

if(vf != null && !RT.booleanCast(vf.invoke(val)))

throw new IllegalStateException("Invalid reference state");

}

catch(RuntimeException re)

{

throw re;

}

catch(Exception e)

{

throw new IllegalStateException("Invalid reference state", e);

}

}

void validate(Object val){

validate(validator, val);

}

public void setValidator(IFn vf){

validate(vf, deref());

validator = vf;

}

public IFn getValidator(){

return validator;

}

public IPersistentMap getWatches(){

return watches;

}

synchronized public IRef addWatch(Object key, IFn callback){

watches = watches.assoc(key, callback);

return this;

}

synchronized public IRef removeWatch(Object key){

watches = watches.without(key);

return this;

}

public void notifyWatches(Object oldval, Object newval){

IPersistentMap ws = watches;

if(ws.count() > 0)

{

for(ISeq s = ws.seq(); s != null; s = s.next())

{

Map.Entry e = (Map.Entry) s.first();

IFn fn = (IFn) e.getValue();

if(fn != null)

fn.invoke(e.getKey(), this, oldval, newval);

}

}

}

}